<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <input type="text" id="input">
    <script>
        var input =document.getElementById("input")
        // var timer;
        // input.addEventListener("keyup",()=>{
        //     if(timer){
        //         clearTimeout(timer)
        //     }
        //   timer =  setTimeout(()=>{
        //         console.log(input.value);
        //         timer =null
        //     },1000)
        // })
        // 封装防抖函数
        var timer;
        function debounce(fn,delay=500){
            if(timer){
                clearTimeout(timer);
            }
            timer =setTimeout(fn,delay)
        }
        input.addEventListener("keyup",()=>{
            debounce(()=>{
                console.log(input.value);
            })
        })
    </script>
</body>
</html>